Apparatus for producing photographic images and printing plates



y 1966 w. SIMM ETAL 3,249,738

APPARATUS FOR PRODUCING PHOTOGRAPHIC IMAGES AND PRINTING PLATES FiledJan. 22, 1965 INVENTORS I WALTER S/MM, H/LDEGARD, HAYDN.

CM L448 TORNEVS) 3,249,738 APPARATUS FOR PRODUCING PHOTOGRAPHIC IMAGESAND PRINTING PLATES Walter Simm, Opladen, and Hildegard Haydn,Leverkusen, Germany, assignors to Agfa Aktiengesellschaft, Leverkusen,Germany, a corporation of Germany Filed Jan. 22, 1963, Ser. No. 253,150Claims priority, application Germany, Feb. 10, 1962,

4 Claims. (Cl. 219216) The invention relates to an apparatus forproducing photographic images and printing plates from a lightsensitivelayer exposed to form an image and a transfer layer in which apparatusthe layers are pressed together and are heated. Images of oppositegradations are produced in the light-sensitive layers and in. thetransfer layer: a negative image is produced in the light-sensitivelayer and a non-laterally-reversed po s-tive copy of the original to bereproduced is obtained in the transfer layer.

Examples of light-senstitive layers are silver halide emulsion layerswhich contain tanning developers. If these layers are heated after theyare exposed to form an image, the exposed areas are hardened, while theunexposed areas are transferred to the transfer layer and serve toproduce a positive image. obtained relief images which can be used asprinting plates. It is also possible to work with silver halide emulsionlayers containing developer substances and with transfer layers whichcontain substances producing.

colored compounds with the developer substances. During heatdevelopment, the developer substances are transferredfro'm the unexposedareas to the transfer layer and there converted byreaction with thesubstances contained there into color images. Those on the exposed areashave been used up for developing the exposed silver halide. Suitablematerials for carrying out these processes are set out in Germanpatent'specifications No. 895,101, 1,003,577, 1,004,043 and 1,015,313and in German Auslegeschrift 1,002,628.

The aforementioned patent specifications disclose the use of dryingdrums 'which can be heated electrically, to heat the layers and to pressthem together. -In such apparatus, the papers are pressed, by means of awaterpervious cloth, onto a heated metal support. It has, however, beenfound that inconsistent results are obtained when using such apparatus.

Heat-copying apparatus is also known which comprise essentially anendless plastic band, which is guided over a plurality of guide rollers,and-a heat radiator, which supplies byradiation the heat necessary todevelop the image. The guiding means are such that the heat-sensitivepaper and the original are pressed, one against the other, between theband and a guide pulley and are irradiated through the band. The copy isformed by imagewise heating of the heat-sensitive paper, initiating areaction which blackens the paper. Apparatus of this type is notsuitable for the aforementioned heat-development processes, since .theserequire entirely different conditions.

It has now been found that these disadvantages may be avoided and thatsatisfactory results may be obtained by using apparatus in which theaforesaid layers are pressed together and heated by a heatable meanshaving water- 'impervious, pressure-tight surfaces.

United States Patent In this way there are having run over the guiderollers, is 20 to 70 C. lower than the temperature of the drum surfaceby cooling during travelling. The temperature of the drum is kept at to250 C., preferably at 150, and is regulated by any conventionalandjusting and maintaining device.

In order to produce satisfactory results, it is expedient to moisten thephotographic materials'with water before introducing themyinto theheating zone. For this purpose, there are used moistening cylinderswhich are so arranged that the photographic materials are moistened fromthe rear under pressure. 4

In the present invention the photographicmaterials to be processed inthe present apparatus are pressed, one against the other, in a closedspace with the simultaneous action of moisture; the steam formed fromthe moisture cannot escape outwardly, but is forced, under pressure, onto the photographic layers. Withthe heating presses and drying drumshitherto employed, these conditions could not be obtained, since avapor-pervious and waterpermeable cloth is used. It is, moreover,desirable for the developing process that there be a temperature drop of20 to 70 C. perpendicular to the plane of the layers which are heatedand pressed together.

The rotational speed of the heating drum is preferably so regulated thatthe photographic layers remain a few .seconds, for example, 5 to 10seconds, in the heating zone. The pressure exerted'by the endless bandon the heating drum is adjusted by means of adjustable guide rollers,preferably to 0.3 to 2 kg./cm.

One embodiment of the apparatus according to the invention is showndiagrammatically in the accompanying drawing in which the apparatusconsists of a drum 1 which can be heated electrically and against whichan endless band 2 of temperature-resistant, elastic, waterimpervious andvapor-tight material of low heat conductivity is so pressed that itcovers a part of the drum periphery, for example half, and almost thefull width of the drum. The width of the band must also be greater thanthe Width of the negative or positive material. A sealed development andtransfer zone is then formed between the drum surface and the band byapplying strong pressure to the band.

The said elastic band can be produced of any material which meets theconditions disclosed above. Suitable are,

for example, silicon rubber on the basis of dimethyl polywith drum 1 andis heated to the reaction temperature,

does not come into contact with any other (colder) elements as it runsover the three guide rollers. As a result, after a few revolutions, thesurface temperature of the band, at the point of contact between theroller 3a and the drum 1, is only slightly lower (20 to 70 C.) than thetemperature of the drum surface. Since the photographic materials 4a and4b are introduced at this point,

there will be the necessary temperature drop across them and, intravelling from the point of insertion between 1 and 3b, they are giventhe further treatment according to the other conditions required. Thetemperature of the drum 1, into which an elecrtical heating arrangementis incorporated, is adjusted so as to be substantially constant, byregulating members which include a fixed rodlike bimetallic strip 5,which projects axially into the rotatably mounted drum and whichassumes, mainly by heat radiation, the temperature of the heated wall ofthe drum '1.

The roller 3c is so mounted that the mounting may be displaced in thedirection indicated by the two arrows and thus the band tension can beadjusted. Since it is desirable for the pressure of the band on the drumat the end of the developing and transfer zone, i.e., the pressurebetween the drum 1 and roller 3b, to be adjustable, the mounting orbearings of the roller 3b may also be displaced inthe directionindicated by the arrow by pressure screws 6 on both bearings.

The support material is moistened by two moistening cylinders 7a and 7b,which are covered with absorbent elastic material and one of which maybe immersed in a tank filled with water. The cylinders 7a, 7b are sodriven, through gearwheels 8a, 8b, 80 from the roller Bar, that a foilpushed a suitable feeding speed between the moistening cylinders. isguided to the inlet position between 3a and 1.

To strip the supporting foils from the drum 1 after they have travelledthrough the development and transfer zone, a stripper plate 9 isarranged in the position indicated.

We claim:

1. Apparatus for producing photographic images for a heat transferprocess from a supported light-sensitive silver halide emulsion layerbeing image wise exposed, developed and heated while in contact with asupported transfer layer, comprising a rotatable drum disposed forreceiving the supported layers with said layers contacting the surfaceof said drum at a feed portion and leaving the surface of said drum at adischarge portion, moistening means disposed adjacent said feed portionof said drum whereby the layers are passed through said moistenin gmeans and on to the surface of said drum, heating means for heating saiddrum, said drum having a vapor tight and water impervious surface uponwhich the layers are in contact, a movable endless belt contacting saidsurface of said drum between said feed portion and said dischargeportion whereby said belt and the portion of said surface of said drumcontacted by said belt form a heating zone,

said endless belt being of a water-impervious elastic material of lowthermal conductivity whereby said heating zone is water impervious, saidendless belt having a temperature between 20 and C. lower than saidsurface of said heating drum, and adjust-able guide means maintainingsaid belt in close contact with said surface of said drum.

2. Apparatus according to claim 1 in which stripping means are disposedat said discharge portion of said drum for separating the layers fromsaid drum.

3. Apparatus according to claim 1, in which said heating means includesa fixed bimetallic rod projecting axially into the rotatably mounteddrum.

4. Apparatus according to claim 1, in which the moistening meansconsists of two moistening rollers positioned on opposite sides of anddisposed for contacting said layers with the centers of said rollerssubstantially aligned with the point of contact of said rollers and saidlayers whereby said layers are simultaneously moistened by pressure fromone side.

References Cited by the Examiner UNITED STATES PATENTS 2,571,426 10/1951 Doniak 219-469 2,770,534 11/1956 Marx 250-65.1 2,891,165 6/1959Kuhrmeyer et .al. 250-651 2,927,210 3/1960 OMara 25065.1 2,986,987 6/1961 Limberger -89 3,012,141 12/1961 Thomiszer 250-65.1 3,027,822 4/1962 Frantz 95-89 3,060,023 10/1962 Burg et a1. 101-1494 3,100,7028/1963 Rauner et al 250-651 3,142,241 7/ 1964 Limberger 95-89 3,148,6129/1964 Jacobs et al 95-89 3,155,024 11/1964 Land 95-89 X RICHARD M.WOOD, Primary Examiner.

RALPH R. NILSON, C. L. ALBRITTON, W. F. LIND- QUIST, Examiners.

1. APPARATUS FOR PRODUCING PHOTOGRAPHIG IMAGES FOR A HEAT TRANSFERPROCESS FROM A SUPPORTED LIGHT-SENSITIVE SILVER HALIDE EMULSION LAYERBEING IMAGE WISE EXPOSED, DEVELOPED AND HEATED WHILE IN CONTACT WITH ASUPPORTED TRANSFER LAYER, COMPRISING A ROTATABLE DRUM DISPOSED FORRECEIVING THE SUPPORTED LAYERS WITH SAID LAYERS CONTACTING THE SURFACEOF SAID DRUM AT A FEED PORTION AND LEAVING THE SURFACE OF SAID DRUM AT ADISCHARGE PORTION, MOISTENING MEANS DISPOSED ADJACENT SAID FEED PORTIONOF SAID DRUM WHEREBY THE LAYERS ARE PASSED THROUGH SAID MOISTENING MEANSAND ON TO THE SURFACE OF SAID DRUM, HEATING MEANS FOR HEATING SAID DRUM,SAID DRUM HAVING A VAPOR TIGHT AND WATER IMPERVIOUS SURFACE UPON WHICHTHE LAYERS ARE IN CONTACT, A MOVABLE ENDLESS BELT CONTACTING SAIDSURFACE OF SAID DRUM BETWEEN SAID FEED PORTION AND SAID DISCHARGEPORTION WHEREBY SAID BELT AND THE PORTION OF SAID SURFACE OF SAID DRUMCONTACTED BY SAID BELT FORM A HEATING ZONE, SAID ENDLESS BELT BEING OF AWATER-IMPERVIOUS ELASTIC MATERIAL OF LOW THERMAL CONDUCTIVITY WHEREBYSAID HEATING ZONE IS WATER IMPERVIOUS, SAID ENDLESS BELT HAVING ATEMPERATURE BETWEEN 20* AND 70*C. LOWER THAN SAID SURFACE OF SAIDHEATING DRUM, AND ADJUSTABLE GUIDE MEANS MAINTAINING SAID BELT IN CLOSECONTACT WITH SAID SURFACE OF SAID DRUM.